The maintenance of normal mitochondrial function varies between organisms as does their oxygen metabolism and response to pathophysiological stress. Although bioenergetic metrics have been surveyed in a broad range of aging models these parameters have yet to be integrated with measures of the control of mitochondrial quality and mitochondrial genetics. We have introduced the concept of Bioenergetic health in translational research and now plan to extend this to models of aging. In the Comparative Mitochondrial Health Assessment core both state of the art and established techniques in bioenergetics, mitochondrial genetics, autophagy and redox biology will be offered. The mechanisms controlling mitochondrial health involve mitochondrial genetics, mitochondrial-nuclear interaction and mitophagy. The novel models offered to the aging community will be the mitochondrial nuclear exchange (MNX) mice which have been pioneered at UAB. This allows the contribution of specific mitochondrial DNA sequences to the process of aging to be assessed independent of the nuclear contribution. State of the art experimental design, and protocols for assessing cellular bioenergetics in response to oxidative and metabolic stress will also be used. As autophagy and mitophagy have been shown to be essential for healthy lifespan, and insufficient autophagy contributes to accumulation of protein aggregates and dysfunctional mitochondria, indices of autophagic flux can be measured. An important aspect of the Core is extending these techniques to a variety of traditional species from yeast to mice, including both cryopreserved ?cell zoo? of fibroblasts from about 60 species of mammals and birds, a lot of these from species of ?exceptional biogerontological interest?, as well as live species that are either exceptionally long-lived or short-lived for their body size, such as the short-lived fish, Nothobranchius furzeri. Specifically, services will be provided to NIA Regular and Supported Members and pilot & feasibility grant awardees in: 1. Molecular energetics analysis including cellular, organelle and tissue measurements, including approaches we have pioneered in spheroid like cell structures and complex multi-cellular structures such as pancreatic islets, vessel segments and adipose tissue, and complementing approaches with targeted metabolomics and oxygen electrodes. 2. Quantitative oxidative stress parameters to assess indices of redox changes including oxidized lipids, thiols and modified proteins. 3. Mitochondrial nuclear exchange (MNX) models, mtDNA damage and haplotyping to test the unique contribution of mtDNA sequences to bioenergetics and the resistance to metabolic and oxidative stress, with approaches available for both the traditional murine models and comparative models of aging used throughout the Center. 4. Autophagy and mitophagy assessments in the context of the pathobiology of oxidative stress and neurodegeneration will be extended to the models of aging. 5. Virtual and wet lab workshop educational programs.